This is a microscope used by an eye doctor to look at the eye. The eye microscope is unique when compared to a traditional microscopes. For one thing, the microscope has been turned on its side so that people can be examined without having to lie down flat. Also, the light-source used can be narrowed to a very narrow beam of light. This light can be angled into the eye to form an illuminated cross-section of the eye … just like how a CAT scan takes cross-section x-ray slices. The eye is the only place in the body that blood vessels and nerves can be seen without opaque skin blocking the view. With a dilated eye exam, the optic nerve (a direct extension off the brain) can be viewed in great detail. Certain systemic conditions can be observed and diagnosed using the slit lamp microscope. For example, diabetes can cause micro-bleeding in the retina (diabetic retinopathy) and inflammatory conditions like rheumatoid arthritis can cause internal ocular inflammation (uveitis). With the slit-lamp microscope and careful technique, individual white blood cells floating in the eye can be detected.